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United States Patent |
5,680,447
|
Diamond
,   et al.
|
October 21, 1997
|
Circuit and method for responding to third party calls in a telephone
system having call waiting
Abstract
A method and circuit which allows a telephone user having a conversation
with a second party in a telephone system having call waiting to
effectively respond to an incoming call from a third party without having
to engage in conversation with the third party. To accomplish this, the
user presses a key on a customer premises equipment (CPE) which initiates
a first flash hook operation which places the second party on hold and
connects the CPE to the third party. A pre-recorded message corresponding
to the pressed key is then transmitted to the third party. The CPE then
performs a second flash hook operation which disconnects the third party
and removes the second party from the hold state. A plurality of keys,
having a corresponding plurality of pre-recorded messages can be provided,
thereby allowing the user to respond to the third party with different
messages. The CPE can include CIDCW capabilities which enable the user to
learn the identity of the third party before selecting the pre-recorded
message.
Inventors:
|
Diamond; Robert L. (Bedford, NY);
Landry; Steven L. (San Jose, CA);
Khojasteh; Kamran (Morgan Hill, CA)
|
Assignee:
|
Cidco, Inc. (Morgan Hill, CA)
|
Appl. No.:
|
457664 |
Filed:
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May 31, 1995 |
Current U.S. Class: |
379/215.01; 379/67.1 |
Intern'l Class: |
H04M 003/42 |
Field of Search: |
379/215,142,201,67,68,127
|
References Cited
U.S. Patent Documents
4661975 | Apr., 1987 | Brecher | 379/215.
|
4873719 | Oct., 1989 | Reese | 379/215.
|
5007076 | Apr., 1991 | Blakley | 379/215.
|
5263084 | Nov., 1993 | Chaput et al. | 379/215.
|
Primary Examiner: Matar; Ahmad F.
Attorney, Agent or Firm: Skjerven, Morrill, MacPherson, Franklin & Friel, MacPherson; Alan H., Hoffman; E. Eric
Claims
What is claimed is:
1. A method for allowing a user of a customer premises equipment (CPE)
engaged in a telephone call with a second party to respond to an incoming
call from a third party in a telephone system having call waiting, wherein
the telephone system generates an alerting signal to alert the user of the
incoming call, the method comprising the steps of:
receiving the alerting signal by the CPE;
monitoring the telephone system by the CPE to determine whether the CPE is
in an off-hook condition;
monitoring a first key of the CPE to determine if the user activates the
first key in response to the received alerting signal;
if the first key is activated by the user in response to the received
alerting signal at any time that the CPE is in an off-hook condition, then
performing a first flash hook operation by the CPE to place the second
party in a hold state and connect the CPE to the third party; and then
transmitting a pre-recorded message corresponding to the first key from the
CPE to the third party; and then
performing a second flash hook operation by the CPE to disconnect the CPE
from the third party, remove the second party from the hold state and
reconnect the CPE to the second party.
2. The method of claim 1, wherein the CPE comprises a telephone, the method
further comprising the steps of:
disconnecting the telephone from the telephone system after the first key
is activated; and
re-connecting the telephone to the telephone system after the second flash
hook operation.
3. The method of claim 1, wherein the CPE comprises a telephone, and
wherein the step of performing the first flash hook operation further
comprises the steps of:
disconnecting the telephone from the telephone system, thereby presenting
an on-hook condition to the telephone system;
coupling a first impedance to the telephone system by the CPE to simulate
the telephone in an on-hook condition; and then
coupling a second impedance to the telephone system by the CPE to simulate
the telephone in an off-hook condition.
4. The method of claim 1, wherein the step of transmitting a pre-recorded
message further comprises the steps of:
retrieving a plurality of digital signals from a memory device; and
generating the pre-recorded message in response to the digital signals.
5. The method of claim 1, further comprising the steps of:
pressing a recording key of the CPE;
announcing an audible message to a microphone of the CPE;
converting the audible message to a plurality of digital signals by the
CPE; and
storing the digital signals in a memory of the CPE as the pre-recorded
message.
6. The method of claim 1, further comprising the steps of:
monitoring a second key to determine if the user activates the second key
in response to the received alerting signal;
if the second key is activated by the user in response to the received
alerting signal at any time that the CPE is in an off-hook condition, then
performing a flash hook operation by the CPE to place the second party in
a hold state and connect the CPE to the third party; and then
transmitting a second pre-recorded message corresponding to the second key
from the CPE to the third party; and then
performing a flash hook operation by the CPE to disconnect the CPE from the
third party, remove the second party from the hold state and reconnect the
CPE to the second party.
7. The method of claim 1, further comprising the steps of:
receiving caller identification information associated with the third party
by the CPE; and
displaying the caller identification information of the third party by the
CPE.
8. A customer premises equipment (CPE) for allowing a user engaged in a
telephone call with a second party to respond to an incoming call from a
third party in a telephone system having call waiting, wherein the
telephone system generates an alerting signal to alert the user of the
incoming call, the CPE comprising:
a first key;
an off-hook detection circuit for determining if the CPE is in an off-hook
condition;
a microcontroller coupled to the first key and the off-hook detection
circuit, wherein the microcontroller monitors the off-hook detection
circuit to determine if the CPE is in an off-hook condition, the
microcontroller further monitoring the first key to determine if the user
activates the first key in response to the alerting signal;
a line termination circuit coupled to the microcontroller, wherein the
microcontroller causes the line termination circuit to perform a first
flash hook operation to place the second party in a hold state and connect
the CPE to the third party placing the incoming call if the
microcontroller detects that the user activates the first key when the CPE
is in an off-hook condition; and
a signal generation circuit coupled to the microcontroller and the line
termination circuit, wherein the microcontroller causes the signal
generation circuit to transmit a pre-recorded message corresponding to the
first key to the third party after the first flash hook operation has been
performed, and further wherein the microcontroller causes the line
termination circuit to perform a second flash hook operation to disconnect
the CPE from the third party, remove the second party from the hold state
and reconnect the CPE to the second party after the prerecorded message is
transmitted.
9. The CPE of claim 8, wherein the signal generation circuit comprises:
a memory device which is programmable to store a plurality of digital
signals representative of the pre-recorded message;
a voice synthesizer circuit coupled to the memory device, wherein the voice
synthesizer circuit generates the pre-recorded message in response to the
digital signals.
10. The CPE of claim 9, wherein the signal generation circuit further
comprises a microphone coupled to the voice synthesizer circuit, whereby
audio signals transmitted to the microphone can be converted into digital
signals and stored in the memory device.
11. The CPE of claim 9, wherein the signal generation circuit further
comprises a speaker coupled to the voice synthesizer circuit, whereby the
pre-recorded message is transmitted to the speaker.
12. The CPE of claim 8, further comprising a second key coupled to the
microcontroller, wherein the microcontroller monitors the second key to
determine if the user activates the second key in response to the alerting
signal, and wherein the microcontroller causes the line termination
circuit to perform a first flash hook operation to place the second party
in a hold state and connect the CPE to the third party if the
microcontroller detects that the user activates the second key when the
CPE is in an off-hook condition, wherein the microcontroller causes the
signal generation circuit to transmit a second pre-recorded message
corresponding to the second key to the third party after the first flash
hook operation has been performed, and further wherein the microcontroller
causes the line termination circuit to perform a second flash hook
operation to disconnect the CPE from the third party, remove the second
party from the hold state and reconnect the CPE to the second party after
the second pre-recorded message is transmitted.
13. The CPE of claim 8, further comprising:
a telephone; and
an interface circuit coupled to the microcontroller, the telephone and the
telephone system, wherein the interface circuit has a first configuration
in which the telephone is connected to the telephone system and a second
configuration in which the telephone is disconnected from the telephone
system, wherein the configuration of the interface circuit is controlled
by the microcontroller.
14. The CPE of claim 8, further comprising:
means for receiving caller identification information of the third party,
wherein the means for receiving are coupled to the telephone system; and
means for displaying the caller identification information of the third
party.
15. The CPE of claim 8, wherein the signal generation circuit produces a
voice message.
16. A method for allowing a user of a customer premises equipment (CPE)
engaged in a telephone call with a second party to respond to a plurality
of incoming calls from one or more third parties, wherein the telephone
system provides an alerting signal to alert the user of the CPE with each
of the incoming calls, the method comprising the steps of:
receiving a first alerting signal associated with a first incoming call
placed by a third party, wherein the alerting signal is received by the
CPE;
actuating a first key by the user in response to the first alerting signal;
sending a first pre-recorded message by the CPE to the third party placing
the first incoming call in response to the actuating of the first key;
receiving a second alerting signal associated with a second incoming call
placed by a third party, wherein the alerting signal is received by the
CPE;
actuating a second key by the user in response to the second alerting
signal;
sending a second pre-recorded message by the CPE to the third party placing
the second incoming call in response to the actuating of the second key,
wherein the first and second pre-recorded messages are different.
17. A customer premises device (CPE) for allowing a user engaged in a
telephone call with a second party to respond to an incoming call from a
third party in a telephone system having call waiting, the CPE comprising:
means for receiving the alerting signal;
means for monitoring the telephone system to determine if the CPE is in an
off-hook condition;
means for monitoring a first key of the CPE to determine if the user
activates the first key in response to the received alerting signal;
means for performing a first flash hook operation to place the second party
in a hold state and connect the CPE to the third party if the first key is
activated by the user in response to the received alerting signal at any
time that the CPE is in an off-hook condition;
means for transmitting a pre-recorded message corresponding to the first
key from the CPE to the third party; and
means for performing a second flash hook operation to disconnect the CPE
from the third party, remove the second party from the hold state and
reconnect the CPE to the second party.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a structure and method for operating a
telephone system. More specifically, the present invention relates to a
structure and method for responding to an incoming telephone call in a
telephone system which implements call waiting (CW) and caller
identification (CID) or a telephone system which implements caller
identification with call waiting (CIDCW).
2. Description of the Prior Art
Call waiting and caller identification are well known concepts in the
telephone industry. With call waiting, a telephone user who is speaking
with a second party on the telephone receives a subscriber access signal
(SAS) tone from the telephone company central office when the user has
another incoming call from a third party. The SAS tone is audible in the
user's telephone receiver. After hearing the SAS tone, the user has the
choice of ignoring the incoming call or answering the incoming call by
pressing a preselected button (or the hookswitch) of the telephone. If the
user answers the incoming call, the second party is placed on "hold."
With caller ID, the telephone company transmits encoded information to the
user's telephone between the first and second ring signals. This encoded
information (caller ID information) typically includes the name and
telephone number of the calling party. The user may purchase or lease
customer premises equipment (CPE) which connects to the user's telephone
line and detects, decodes and displays the encoded information. For the
CPE to properly process the caller ID information, the telephone must be
in an on-hook condition when the caller ID information is received. As
used herein, the term "on-hook" refers to the condition which generally
exists when the handset of the telephone is resting on the hookswitch of
the telephone and the term "off-hook" refers to the condition which
generally exists when the handset of the telephone is removed from the
hookswitch of the telephone.
Caller ID and call waiting can both be separately implemented by a
telephone user. This system is referred to as a caller ID and call waiting
(CID & CW) system. In a CID & CW system, the user receives and displays
caller ID information when a second party calls the user and the user's
telephone is in an on-hook condition. Additionally, the user will receive
a SAS tone when a third party calls while the user is talking to the
second party. Although the user is informed when a third party is calling,
the user does not receive the caller ID information of the third party.
The two concepts of caller ID and call waiting have also been combined to
create caller ID with call waiting (CIDCW). CIDCW requires that the
telephone user have a CPE (or the equivalent) connected to the telephone
line. When the user is speaking on the phone with a second party and
receives a call from a third party, a SAS tone followed by a CPE alerting
signal (CAS) tone is transmitted from the telephone company central office
to the user's CPE. The CAS tone is similar to a dual tone multi-frequency
(DTMF) signal, but has higher frequencies and is of a lower amplitude. The
CPE detects the CAS tone and then transmits an acknowledge signal to the
telephone company central office. The acknowledge signal has been defined
to be the DTMF signal "D". During the transmission of the acknowledge
signal, the CPE disconnects the voice path of the user's telephone and the
telephone company central office mutes the acknowledge signal so that the
second party does not hear the acknowledge signal. Upon detecting the
acknowledge signal, the telephone company transmits the caller ID
information to the user's CPE. The CPE detects and displays the third
party's caller ID information and communication is re-established with the
second party.
In both CID & CW systems and CIDCW systems, the user may not wish to speak
with the third party immediately, but would rather continue the ongoing
conversation with the second party. In both CID & CW systems and CIDCW
systems, if the user does not answer the third party's call, the third
party hears continued ringing. Thus, the third party typically does not
know whether the user is on the phone with a second party or whether the
user is not home. Therefore, if the user does not answer the third party's
call, the third party typically obtains no useful information from the
user. Additionally, the user can not provide any useful information to the
third party without answering the third party's call.
If the user does answer the third party's call in an attempt to briefly
assure the third party that the user is available (in a CID & CW system)
or that the caller ID information was received and that the user will
later return the third party's call (in a CIDCW system), the user runs the
risks of (1) being detained by the third party, thereby undesirably
interrupting the conversation with the second party and/or (2) appearing
rude in attempting to limit the conversation with the third party to only
a brief message.
It would therefore be desirable to have a structure and method which would
provide a telephone user with more flexibility in responding to third
party calls in telephone systems which implement CID & CW and CIDCW.
SUMMARY
Accordingly, the present invention provides a circuit having one or more
keys, each of which can be pressed to transmit a pre-recorded message to a
third calling party in a CID & CW system or a CIDCW system.
In a CID & CW system, when the user is talking to a second party and
receives a SAS tone which indicates that a third party is calling, the
user can press a key which transmits a pre-recorded message to the third
party. This message can state, for example, "I'm currently on the phone
with another party. Please call again in several minutes." Alternatively,
several keys can be provided such that the user can give the third party
an estimate as to how long the conversation with the second party will
last. In such a system, a first key may instruct the third party to call
back in five minutes and a second key may instruct the third party to call
back in a half an hour.
In a CIDCW system, when the user is talking to a second party and receives
caller ID information concerning an incoming call from a third party, the
user can press a key which transmits a pre-recorded message to the third
party. This message can state, for example, "I'm currently on the phone
with another party. I have your caller ID information and will call you
back when I complete my current conversation." Several keys can be
provided such that the user can give the third party an estimate as to how
long the conversation with the second party will last.
Such a system advantageously allows the user to dispose of the third party
without substantially interrupting the conversation with the second party
and without a confrontation with the third party.
More specifically, the present invention includes a method for allowing a
user engaged in a telephone call with a second party to respond to an
incoming call from a third party. The method can be implemented in either
a CID & CW system or a CIDCW system. The method includes the step of
monitoring a first key to determine if the first key is pressed. If the
first key is pressed, a first flash hook operation is performed, thereby
providing a connection to the third party and placing the second party on
"hold". A pre-recorded message associated with the first key is
transmitted to the third party and a second flash hook operation is
performed, thereby re-connecting the second party. In a particular
implementation, the user's telephone is temporarily disconnected from the
telephone system during the time that the pre-recorded message is
transmitted.
In another embodiment, additional keys are added, with each key having a
corresponding pre-recorded message.
The pre-recorded message can be a standard message or can be a personalized
message recorded by the user. The pre-recorded message can be stored in a
memory device as a plurality of digital signals which are transmitted to a
voice synthesizer circuit to generate a voice message.
In a particular implementation, the method can include the steps of
monitoring the telephone system to determine whether the telephone is in
an off-hook condition and transmitting the pre-recorded message to the
third party only if the telephone is in an off-hook condition.
The present invention also includes a circuit which allows a user engaged
in a telephone call with a second party to respond to an incoming call
from a third party. The circuit can be used in telephone systems having
CID & CW or CIDCW. The circuit includes a microcontroller, a first key, a
line termination and signal transmission path circuit, an off-hook detect
circuit and a signal generation circuit. The first key is coupled to the
microcontroller such that the microcontroller can monitor the first key to
determine if the first key is pressed. The line termination and signal
transmission circuit is coupled to the telephone system and the
microcontroller. If the first key is pressed, the microcontroller causes
the line termination and signal transmission circuit to change an
impedance coupled to the telephone system, thereby causing a first flash
hook operation. The off-hook detect circuit, which determines whether the
telephone is in an off-hook condition, is coupled to the telephone system
and the microcontroller. The signal generation circuit is coupled to the
telephone system and the microcontroller and transmits a pre-recorded
message to the telephone system if the first key is pressed and the
telephone is in an off-hook condition. This circuit can be modified to
include additional keys and additional corresponding pre-recorded
messages.
The signal generation circuit can include a memory device which is
programmable to store a plurality of digital signals representative of the
pre-recorded message and a voice synthesizer circuit coupled to the memory
device. The voice synthesizer circuit generates the pre-recorded message
in response to the digital signals. The signal generation circuit can
further include a microphone and/or a speaker, whereby personalized
messages can be recorded and reviewed.
The present invention will be more fully understood in view of the
following description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a CPE according to one embodiment of the
present invention;
FIG. 2 is a block diagram of the line termination and voice transmission
path circuit of FIG. 1;
FIGS. 3 and 4 are flow diagrams illustrating operation of the CPE of FIG. 1
in accordance with one embodiment of the invention;
FIG. 5 is a block diagram of a CPE according to another embodiment of the
present invention; and
FIG. 6 is a flow diagram illustrating operation of the CPE of FIG. 5 in
accordance with an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates CPE 100 in accordance with one embodiment of the
invention. CPE 100 is coupled to a telephone company central office via
tip line 10 and ring line 11. CPE 100, which is intended for use in a CID
& CW system, includes ring detect circuit 101, telephone line interface
circuit 102, off-hook detect circuit 103, line termination and voice
transmission path circuit 105, frequency shift keying (FSK) detector
circuit 106, microcontroller 109, LCD display 114, caller ID memory 115,
voice generation circuit 120 and keys 151-152.
Ring detect circuit 101, telephone line interface circuit 102, FSK detector
circuit 106, microcontroller 109, display 114 and caller ID memory 115
allow CPE 100 to operate as a conventional CPE in a CID & CW system. These
circuit elements are briefly summarized below. Telephone line interface
circuit 102 connects CPE 100 to tip and ring lines 10 and 11. Interface
circuit 102 includes switches 102a and 102b which either (1) connect
telephone 190 to tip and ring lines 10 and 11 in parallel with CPE 100 or
(2) disconnect telephone 190 from tip and ring lines 10 and 11. Switches
102a and 102b are under the control of microcontroller 109. During the
mode of operation of CPE 100 in which the user is conversing with the
second party, telephone 190 is connected to tip and ring lines 10 and 11.
Interface circuit 102 connects tip and ring lines 10 and 11 to ring detect
circuit 101. Ring detect circuit 101 is a conventional circuit which
detects the ring signals transmitted by the telephone company central
office when a second party calls the user. One embodiment of ring detect
circuit 101 is described in more detail in commonly owned, co-pending U.S.
patent application Ser. No. 08/388,108, entitled "CALLER ID AND CALL
WAITING FOR MULTIPLE CPEs ON A SINGLE TELEPHONE LINE", by Harry W. Lewis,
filed Feb. 13, 1995, herein incorporated by reference in its entirety.
Each time ring detect circuit 101 detects a ring signal, ring detect
circuit 101 transmits a signal to microcontroller 109 to indicate that a
ring signal was received.
Interface circuit 102 also connects tip and ring lines 10 and 11 to FSK
detector circuit 106. FSK detector circuit 106 is a conventional circuit
which detects and decodes caller ID information transmitted by the
telephone company central office as FSK signals. One embodiment of FSK
detector circuit 106 is described in commonly owned, co-pending U.S.
patent application Ser. No. 08/388,108, hereby incorporated by reference.
FSK detector circuit 106 transmits the decoded caller ID information to
microcontroller 109. Microcontroller 109, which is a conventional
controller available from manufacturers such as Intel or Motorola, is
connected to LCD display 114 and caller ID memory 115, thereby allowing
the decoded caller ID information to be transmitted to display 114 and
caller ID memory 115. LCD display 114 and caller ID memory 115 display and
store the caller ID information.
In addition to the previously described circuitry, CPE 100 includes
off-hook detect circuit 103, line termination and voice transmission path
circuit 105, voice generation circuit 120 and keys 151-152.
FIG. 2 is a block diagram which illustrates line termination and voice
transmission path circuit 105 in more detail. Line termination and voice
transmission path circuit 105 includes polarity guard circuit 161, phone
line switch 162 and line hold and signal injection circuit 163. Polarity
guard circuit 161 is a conventional full wave bridge circuit coupled to
tip and ring lines 10 and 11. Polarity guard circuit 161 outputs a
positive voltage with respect to ground (i.e., the voltage across tip and
ring lines 10 and 11), even when the tip and ring lines ar reversed due to
miswiring.
Phone line switch 162 is connected between microcontroller 109 and polarity
guard circuit 161. Phone line switch 162 includes circuitry which
terminates and un-terminates tip and ring lines 10 and 11 in response to
signals received from microcontroller 109. That is, phone line switch 162
can vary the impedance across tip and ring lines 10 and 11 to simulate
on-hook and off-hook conditions.
Line hold and signal injection circuit 163 is coupled between voice
generation circuit 120 and phone line switch 163. Line hold and signal
injection circuit 163 provides a signal transmission path from voice
generation circuit 120 to tip and ring lines 10 and 11. This signal
transmission path is controlled by microprocessor 109. One embodiment of
polarity guard circuit 161, phone line switch 162 and line hold and signal
injection circuit 163 is described in more detail in commonly owned,
co-pending U.S. patent application Ser. No. 08/388,108, hereby
incorporated by reference.
Off-hook detect circuit 103 is coupled to receive the positive voltage
provided by polarity guard circuit 161 of line termination and voice
transmission path circuit 105. Off-hook detect circuit 103 monitors this
voltage (i.e., the voltage across tip and ring lines 10 and 11) to
determine whether telephone 190 is in an on-hook or off-hook condition. If
the voltage across tip and ring lines 10 and 11 is less than a
predetermined voltage (e.g., approximately 18 volts, .+-.1 volt), off-hook
detect circuit 103 transmits a signal to microcontroller 109 to indicate
that telephone 190 is in an off-hook condition. Conversely, if the voltage
across tip and ring lines 10 and 11 exceeds the predetermined voltage,
off-hook detect circuit 103 transmits a signal to microcontroller 109 to
indicate that telephone 190 is in an on-hook condition. One embodiment of
off-hook detect circuit 103 is described in more detail in commonly owned,
co-pending U.S. patent application Ser. No. 08/388,108, hereby
incorporated by reference.
In an alternative embodiment, the blocks of CPE 100 are incorporated into
telephone 190. In such an embodiment, the stand-alone CPE structure is
eliminated because telephone 190 now supports the features previously
supported by CPE 100. In this embodiment, off-hook detect circuit 103 can
be replaced with the conventional switch hook detect circuit (not shown)
present in telephone 190. This switch hook detect circuit monitors the
action of the hand-set being lifted off the telephone set.
Microcontroller 109 is also connected to voice generation circuit 120.
Voice generation circuit 120 includes message storage device 121, voice
synthesizer circuit 122, record and playback circuit 123, speaker 124,
microphone 124, record key 126 and playback key 127. In other embodiments,
voice generation circuit 120 can include other signal generation circuits,
which generate tones or other non-voice messages.
Message storage device 121 is a memory which is capable of storing one or
more digitized voice messages which correspond to keys 151 and 152. For
example, storage device 121 can store a first digitized voice message
corresponding to key 151 and a second digitized voice message
corresponding to key 152. These first and second digitized voice messages
can be stored at predetermined first and second initial addresses,
respectively, within storage device 121. Although only two keys 151-152
are illustrated, other numbers of keys and messages can be used.
In a particular embodiment, storage device 121 is a read only memory (ROM)
which is pre-loaded with standard messages before CPE 100 is provided to
the user. In such an embodiment, record and playback circuit 123, speaker
124 and microphone 125 need not be utilized. In another embodiment,
storage device 121 is a programmable volatile memory device such as static
random access memory (SRAM) or dynamic random access memory (DRAM). When
storage device 121 is implemented as SRAM or DRAM, a battery is required
to maintain the contents of storage device 121 during a loss of power.
Storage device 121 can also be a programmable non-volatile memory device
such as an EPROM or an EEPROM. If storage device 121 consists of a
programmable memory, storage device 121 can be pre-loaded with standard
messages or can be programmed by the user to include personalized messages
as described in more detail below.
Message storage device 121 is coupled to voice synthesizer circuit 122.
Voice synthesizer circuit 122 is a conventional circuit which is available
from manufacturers such as OKI Semiconductor (as part no. MSM6258). Voice
synthesizer circuit 122 receives a signal from microcontroller 109 when
one of keys 151-152 is pressed. In response, voice synthesizer circuit 122
accesses the digitized message in storage device 121 which corresponds to
the pressed key. Voice synthesizer circuit 122 thereby receives a stream
of digital signals from storage device 121 and in response generates an
analog signal representative of a human voice. This analog signal is
transmitted from voice synthesizer circuit 122 to tip and ring lines 10
and 11 through line termination and voice transmission path circuit 105.
Voice synthesizer circuit 122 is also coupled to record and playback
circuit 123, speaker 124 and microphone 125. Using these elements, the
user can store personalized messages in storage device 121. To store a
personalized message, the user presses record key 126, thereby causing
record and playback circuit 123 to couple microphone 125 to voice
synthesizer circuit 122. Record and playback circuit 123 also transmits a
signal to microcontroller 109 to indicate that record key 126 was pressed.
Microcontroller 109 detects the pressing of record key 126 and instructs
voice synthesizer circuit 122 to enter a recording mode. The user then
speaks a personalized message into microphone 125, thereby causing record
and playback circuit 123 to generate an analog voice signal. Record and
playback circuit 123 optionally provides filtering and amplification to
the signal received from microphone 125. The analog voice signal is
transmitted from record and playback circuit 123 to voice synthesizer
circuit 122. In the recording mode, voice synthesizer circuit 122
digitizes the analog voice signal and routes the digitized signal to
storage device 121.
When the user has completed reciting the message, the user presses the key
which is to correspond to the recorded message (e.g., key 151).
Microcontroller 109 detects this key press and, in response, causes the
digitized signal to be stored beginning at an address within storage
device 121 which corresponds to the depressed key (e.g., key 151). In
addition, microcontroller 109 causes record and playback circuit 123 to
disconnect microphone 125 from voice synthesizer circuit 123 and instructs
voice synthesizer 122 to exit the recording mode.
By pressing playback key 127 followed by the programmed key (e.g., key
151), the user can review the message stored in storage device 121. Upon
pressing playback key 127, record and playback circuit 123 couples speaker
124 to voice synthesizer circuit 122. Record and playback circuit 123 also
transmits a signal to microcontroller 109 to indicate that playback key
127 was pressed. The user then presses the key which corresponds to the
recorded message to be reviewed (e.g., key 151). Microcontroller 109
detects the pressing of the programmed key and instructs voice synthesizer
circuit 122 to enter a playback mode. In playback mode, voice synthesizer
circuit 122 retrieves the digitized voice signal corresponding to the
programmed key from storage device 121. Voice synthesizer circuit 122
converts the digitized voice signal to an analog voice signal, which is
transmitted through record and playback circuit 123 to speaker 124 for the
user's review. In an alternate embodiment, record key 126 and playback key
127 can be coupled directly to microcontroller 109.
Voice synthesizer circuit 122 is also coupled to line termination and voice
transmission path circuit 105. As described in more detail below, if one
of keys 151 or 152 is pressed, and neither of record or playback keys 126
or 127 is pressed, microcontroller 109 instructs voice synthesizer circuit
122 to access the digitized voice signal in storage device 121 which
corresponds to the pressed key. Voice synthesizer circuit 122 converts
this digitized voice signal to an analog voice signal which is transmitted
to tip and ring lines 10 and 11 through line termination and voice
transmission path circuit 105.
FIGS. 3 and 4 are flow diagrams which illustrate the operation of
microcontroller 109 of CPE 100 in accordance with one embodiment of the
invention.
Microcontroller 109 begins with main processing routine 201. Processing
proceeds to step 202 in which other tasks are processed. These other tasks
can include, for example, processing time/date information, processing
requests entered by record key 126 or playback key 127 or monitoring the
battery power of CPE 100. When Step 202 is completed, microcontroller 109
monitors the signal received from off-hook detect circuit 103 to determine
whether telephone 190 is in an on-hook or off-hook condition (Step 203).
The signal from off-hook detect circuit 103 is a digital signal having a
first state and a second state. The state of the digital signal indicates
whether telephone 190 is in an on-hook or an off-hook condition.
If telephone 190 is in an on-hook condition, processing proceeds to step
204 in which microcontroller 109 monitors the signal received from ring
detect circuit 101 to determine whether a ring signal has been detected.
If a ring signal is not detected, processing returns to step 202. If a
ring signal is detected, processing proceeds to step 205, in which caller
ID information is processed in a conventional manner. Thus, if telephone
190 is in an on-hook condition, the pressing of keys 151-152 cannot
activate voice generation circuit 120.
If telephone 190 is determined to be in an off-hook condition in Step 203,
processing proceeds to voice message relay (VMR) subroutine 300 (FIG. 4).
Subroutine 300 begins with Step 301, in which microcontroller 109
determines whether either of keys 151 or 152 has been pressed. If neither
of keys 151-152 has been pressed, processing returns to Step 201.
If the user desires to send a message to the third party in response to
having heard the call waiting tone, the user may do so by pressing key 151
or 152. If one of keys 151 or 152 has been pressed, processing proceeds to
Steps 302-308. In Step 302, microcontroller 109 disconnects telephone 190
from tip and ring lines 10 and 11 by actuating switches 102a and 102b.
This effectively places CPE 100 in an on-hook condition because tip and
ring lines 10 and 11 are not terminated.
In Step 303, microcontroller 109 causes line termination and voice
transmission path circuit 105 to disconnect tip and ring lines 10 and 11,
thereby preventing CPE 100 from drawing any load current. This effectively
causes CPE 100 to remain in an on-hook condition. In Step 304,
microcontroller 109 causes line termination and voice transmission path
circuit 105 to load tip and ring lines 10 and 11, effectively placing CPE
100 in an off-hook condition.
Together, Steps 303 and 304 perform a first flash hook sequence. This flash
hook sequence is equivalent to the user pressing and releasing the
hookswitch of telephone 190. In a system which utilizes call waiting, a
flash hook sequence allows the user to put the second party on hold and
speak to the third party. Thus, at the completion of Step 304, CPE 100 is
connected to the third party and the second party is on hold.
At this time, microcontroller 109 causes voice synthesizer circuit 122 to
access the digital voice signal in storage device 121 which corresponds to
the pressed key 151 or 152 (Step 305). In Step 306, voice synthesizer
circuit 122 converts the selected digital voice signal to an analog voice
signal. Microcontroller 109 activates voice synthesizer circuit 122,
thereby transmitting the analog voice signal to tip and ring lines 10 and
11 through line termination and voice transmission path circuit 105. The
analog voice signal is received by the third party as a voice message.
During the time that the voice message is transmitted, the second party is
placed on hold.
Various messages can be transmitted to the third party. For example,
storage device 121 can store a predetermined message corresponding to key
151 which states, "I'm currently on the phone with another party. Please
call again in five minutes." Storage device 121 can also store a
predetermined message corresponding to key 151 which states, "I'm
currently on the phone with another party. Please call again in thirty
minutes." Such messages will provide useful information to the third party
without requiring the user to speak to the third party. Other
predetermined messages are contemplated and within the scope of the
invention.
Record and playback circuit 123 can be used to record messages which are
specific to certain occasions. For example, if the user is about to make
an important phone call which cannot be interrupted, the user may record a
message such as, "I'm currently on the phone with the president. I expect
the conversation to be over at two o'clock. Please call back after this
time." Other personalized messages are contemplated.
After the message has been transmitted to the third party, microcontroller
109 again causes line termination and voice transmission path circuit 105
to disconnect tip and ring lines 10 and 11, thereby preventing CPE 100
from drawing any load current. This effectively places CPE in an on-hook
condition (Step 307). In Step 308, microcontroller 109 re-connects
telephone 190 to tip and ring lines 10 and 11 by actuating switches 102a
and 102b. Because telephone 190 is in an off-hook condition, a second
flash hook operation is performed by steps 307 and 308. This second flash
hook operation re-establishes the connection to the second party and
places the third party on hold. The user can then continue the
conversation with the second party. Because the user does not have to
speak to the third party, there is no chance that the third party can
interrupt the conversation with the second party.
FIG. 5 is a block diagram illustrating CPE 400 in accordance with another
embodiment of the invention. CPE 400 is intended for use in a system in
which the telephone company central office provides caller ID with call
waiting (CIDCW) service. CPE 400 uses many of the same elements as CPE 100
(FIG. 1). Elements of CPE 400 which are similar to elements of CPE 100 are
labeled with the same reference numbers. Moreover, CPE 400 operates in a
manner similar to CPE 100. However, as described in more detail below, CPE
400 allows the caller ID information of the third party to be displayed on
display 114 before the user presses one of keys 151-152 to respond to the
third party. Because the user is aware of the third party's identity, the
user can better decide which message to transmit to the third party.
In addition to the blocks present in CPE 100, CPE 400 also includes CAS
detect circuit 401 and DTMF generator circuit 402. CAS detect circuit 401
is coupled to tip and ring lines 10 and 11 through FSK detector circuit
106. CAS detect circuit 401 monitors tip and ring lines 10 and 11 to
determine when a CAS tone is present on these lines. As previously
described, the CAS tone is a tone generated by the telephone company
central office when the user is speaking to a second party and a third
party calls the user. CAS detect circuit 401 transmits a signal to
microprocessor 109 when a CAS tone is detected.
DTMF generator circuit 402 is coupled to microcontroller 109. After a CAS
tone is detected, microcontroller 109 transmits a signal to DTMF generator
circuit 402, thereby causing DTMF generator circuit 402 to generate an
acknowledge signal. This acknowledge signal is transmitted to tip and ring
lines 10 and 11 through line hold and signal injection circuit 163, phone
line switch 162 and polarity guard circuit 161 (FIG. 2). The acknowledge
signal can be transmitted using the same path used to transmit signals
from voice generation circuit 120 to line termination and voice
transmission path circuit 105. Alternatively, separate paths to line
termination and voice transmission path circuit 105 can be provided for
DTMF generator circuit 402 and voice generation circuit 120. The
acknowledge signal is transmitted to the telephone company central office
on tip and ring lines 10 and 11. Upon receiving the acknowledge signal,
the central office transmits the caller ID information of the third party
to CPE 400 on tip and ring lines 10 and 11. This caller ID information is
processed as previously described and displayed on display 114.
FIG. 6 is a flow diagram illustrating the operation of CPE 400. The steps
of FIG. 6 are similar to the steps of FIG. 3. Similar steps are labeled
with the same numbers. In FIG. 6, if an off-hook condition is detected in
Step 203, processing proceeds to Step 501 in which microprocessor 109
determines whether a CAS tone has been detected by CAS detect circuit 401
(FIG. 5). If no CAS tone has been detected, processing continues with Step
201. If a CAS tone has been detected, microcontroller 109 causes DTMF
generator 402 (FIG. 5) to generate an acknowledge signal (Step 502).
Microcontroller 109 then receives the caller ID information of the third
party from FSK detector circuit 106 (FIG. 5) and displays this information
on display 114 (Step 503). Processing then proceeds to voice message relay
subroutine 300 (FIG. 4).
Because CPE 400 provides the user with the caller ID information of the
third party, the user can select a response in a more informed manner. For
example, key 151 may correspond to the message: "I'm currently on the
phone with another party. I have your caller ID information and will call
you back when I complete my current conversation." In addition, key 152
may correspond to a message intended to deter solicitors or other unwanted
calls, such as: "I'm sorry, but the party you have called does not wish to
accept your call." Many other messages are contemplated and within the
scope of the invention.
While the present invention has been described in connection with a
particular embodiment, it is understood that the invention is not limited
to the embodiment disclosed, but is capable of various modifications which
would be apparent to one of ordinary skill in the art. Thus, the present
invention is limited only by the following claims.
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